PbrMYB31–PbrbHLH147 complex activity in response to ABA promotes fatty acid biosynthesis for suberin deposition in the russet mutant of ‘Dangshansuli’

Abstract

Suberin is a naturally occurring polymer found in plant cell walls that plays crucial roles in protecting plants from environmental stress and enhancing resistance to pathogens. Despite its biological importance, the molecular regulatory networks governing suberin biosynthesis are not fully understood. In the russet pericarp of ‘Dangshanjinsu’ pear, suberin accumulation, which is enriched with very long-chain fatty acids, contributes to the formation of a robust protective barrier. Transcriptome data analysis revealed that PbrMYB31 and PbrbHLH147 were the key differentially expressed transcription factors in the pericarp of both ‘Dangshansuli’ and ‘Dangshanjinsu’ at various developmental stages. In this study, overexpression of PbrMYB31 and PbrbHLH147 was found to positively regulate long-chain fatty acid synthesis, promote suberin formation, and increase sensitivity to abscisic acid (ABA). Additionally, PbrMYB31 interacts with PbrbHLH147, forming a regulatory complex that synergistically extends the carbon chain length of fatty acids, a critical step in suberin assembly. ABA signaling was shown to integrate into this pathway, further modulating suberin production and linking hormonal regulation with structural barrier formation. This study provides novel insights into the genetic and hormonal control of suberin biosynthesis in russeted pear pericarp, emphasizing its critical role in enhancing fruit protection, improving quality, and extending shelf life, thereby contributing to advancements in horticultural science and sustainable fruit production.